The invention concerns a securing device for swivelling components of vehicles, in particular for engine hoods of motor vehicles, of the type given in the preamble to the main claim.
Such a device can be taken as already known from German Patent Document DE-PS 23 64 466, in which the manipulator is linked to the securing hook and in which the control edge is part of the securing hook. By this means, the pivoting advancement of the securing hook as far as its catch position (caused by the control edge) and the advancement displacement of the manipulator between its position recessed into a radiator grille and its operating position protruding out of the radiator grille are in a direct relationship. If the advancement displacement of the manipulator should be increased, e.g. so that a more easily gripped manipulator can be used, the securing hook itself must also be increased by a corresponding amount.
The securing hook must, however, be reliably able to fulfill its catch function even in driving operation when the lock of the engine hood is accidentally released and the engine hood moves rapidly upwards, supported by the dynamic pressure of the wind relative to the vehicle.
An increased mass of the resulting securing hook swinging towards the front would then have to be compensated by a correspondingly strong return spring, which again would have disadvantageous effects on the manipulator operating forces.
Also known from German Patent Document DE-OS 28 54 423 is a grip arrangement for a swivelling component of vehicles in which a manipulator is swivelled from a recessed at-rest position into a release position suitable for operation as soon as a locking of the swivelling component has been canceled. For this purpose, a control hook is provided which is supported so that it can swivel; this control hook is located on the swivelling component and is moved in the opening direction by sliding along the mating component. By this means, it controls a stored spring-energy drive for the manipulator and a securing element for an end position of the manipulator.
However, the known arrangement does not include a securing hook which, after the release of the swivelling component, must initially maintain a catch connection between the latter and the corresponding mating component. In consequence, the problems associated with unintended cancellation of such a catch connection because of a design increase in the manipulator advancement do not appear at all.
In addition, the control of the known grip arrangement is extremely complicated so that it could hardly be used in the case of a securing hook because of the installation space required, as is already known from German Patent Document DE-PS 23 64 466.
An object of the invention is, therefore, to further develop a securing device of the generic type in such a way that, while retaining its compact construction, an increase in the automatic manipulator advancement is possible without doubts about safety and without sacrifices in the operating comfort of the securing device.
This object is achieved in the invention by an arrangement wherein the control edge is part of a control hook which is supported so that it can swivel with motion relative to the securing hook near the latter and in an approximately parallel plane, a drive feature protruding from one of the control hook and securing hook and penetrating transverse to the plane of swivelling of the corresponding other one of the control hook and securing hook, by means of which drive feature the motion of the control hook is coupled to that of the securing hook only after it is in advance of the latter.
Because the control hook is formed separately from the securing hook, the control edge can be designed to produce the largest possible advancement of the manipulator without having to take account of the hook shape. On the other hand, the securing hook can also be optimized with respect to strength because the way it is shaped no longer has any effect on the curve of the control edge. Because the swivelling planes of the control hook and the securing hook are located in adjacent mutually parallel planes, the particularly simple coupling of the motion of the two hooks by means of a rigid drive feature is ensured, the advance of the control hook relative to the securing hook being fixed by the arrangement of the drive feature.
The amount of control hook advance is preferably selected in such a way that the motion of the control hook is only coupled with that of the securing hook in the operating position of the manipulator. In consequence, the securing hook does not take part in the automatic forward-swinging movement of the control hook; it retains its catch position unaltered.
A particularly simple way of coupling the motion of the control hook with that of the securing hook can be achieved by means of a rigid drive feature protruding from one of the two interacting components, provided the pivoting planes of the control hook and the securing hook are located in adjacent and mutually parallel planes.
In order to achieve a simple construction of the device, the securing hook and the control hook can be supported on a common hinge pin. For manufacturing reasons, it is desirable to shape the drive feature on the control hook according to especially preferred embodiments.
In the case of a plate-shaped control hook, the drive feature preferably consists of a plate stop which protrudes at right angles from one wide side of the control hook and makes contact as an area with a rear edge of the securing hook. Because of the area contact of the plate stop on the rear edge of the securing hook, the demands made on the bending stiffness of the plate stop are reduced to a minimum.
An extension of the plate stop by a hook-shaped guide strap at an angle can then ensure that the plate stop cannot slip from the rear edge of the securing hook because, for example, of its own bending. In addition, the demands made on the bearing precision of the control hook can be substantially reduced as a result.
In the interest of the greatest possible functional reliability, it is advantageous for both the control hook and the securing hook to be loaded by means of their own return springs. In the case of one of the return springs fracturing, a return force can, by this means, be transmitted to both components by the functioning return spring if, in addition to the plate stop, a further drive stop is provided which acts in the reverse swivelling direction.
With the limitation of an unintentional and erroneous release of the hood lock while travelling, the securing device remains functional even without any spring-loading on the control hook or the securing hook if both the securing hook and the control hook have a corresponding return lug.
A control hook consisting of plastic can be manufactured at favorable cost by an injection molding method, for example, and such a hook is characterized by the fact that its own weight is relatively low.
The resulting low acceleration mass of the control hook, relative to metallic materials, contributes to a further increase in the safety reserves of the device.
In addition, the return spring associated with the control hook can be dimensioned to be weaker, which contributes to the operating comfort when pulling the manipulator.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.